The present invention relates generally to a signal transmission over an optical fiber system implemented with optical fibers and related optical components. More particularly, this invention relates to a new tap output optical collimator with improved configurations for low cost production.
For optical signal transmission over an optical fiber system, there is a need to monitor the optical power in and out of optical devices or an optical system such as fiber amplifier and variable attenuator. A common method employed in conventional fiber optical system is to connect a tap optical coupler to the input end or/and the output end of the fiber pigtail of the devices or the system. A small amount of light power is directed from the input or output as a reference to monitor the input or/and output optical power. Such approach however suffers several drawbacks. The size of the signal transmission is increased with one more optical element is added. Stability of optical signal transmission and tapped output measurement may be degraded if the coupling between the tap coupler to the collimator is not properly connected. Signal power loss may also occur due the requirement of transmitting the signal through the tap optical coupler as an additional optical element. The simplest way to solve the problem is to use taped optical collimator to assembly the device that has built-in tap collimator to direct a portion power form input or/and output side. The tap-input collimator is commercially available. It is made by a dual fiber collimator in that two fiber is parallel placed side by side in a glass capillary and share a same collimator lens, prefer ably the GRIN lens. When a input light is coupled into one fiber of such input tap collimator, since the fiber is positioned in the dual core glass capillary and the fiber core is off-axis of the GRIN lens, the collimated beam has a declined angle against the axis of GRIN lens. A part of the beam is reflected from the far-end of GRIN lens surface or from a partial reflector glued on the GRIN lens surface. The reflected part of the beam receives an equal opposite decline angle from the reflector and is focused by the same GRIN lens to another finer in the glass capillary. The second fiber is the tap fiber carrying the tap power. The main portion of the light pass through the partial reflection glass piece to provide ongoing collimated beam.
However, the tap-output collimator is not yet made available mainly because of difficulties to divide incoming light beam into two beams in proper ration with opposite declined angle to project two beams into two fibers in a dual fiber glass capillary respectively.
For these reasons, there is a need in the art of optical fiber signal transmission to provide a new and improved apparatus and method for tapping out a small portion of received signal power from a collimator for measuring and monitoring the optical signal transmission. Preferably, the new and improved configurations and methods are simple and easy to implement with compact configuration for low cost production.
It is therefore an object of the present invention to provide a new and improved design and configuration for manufacturing and assembling a tap output collimator for directly projecting a small portion of optical beam to a tap output fiber for measuring and monitoring the signal transmission. By integrating a function of tap-out projection to a collimator, a stable, low cost and simplified configuration and process of manufacture are achieved and the difficulties of the prior art are resolved.
Specifically, it is an object of the present invention to integrate a means for tap-out projection to a collimator by building into collimator a means for projecting a small portion of light beam to a tap-out fiber for measurement. The tap-out projection can be implemented with many types of optical arrangements. In one preferred embodiment, the tap-out projection is integrated with the collimator by a prism. In another preferred embodiment, the tap-out projection is implemented with a built-in reflection mirror. By integrating the tap-out projection function into a collimator, the size and production cost of tap out monitoring are reduced, more stable operation is achieved and the transmission loss is reduced.
Briefly, in a preferred embodiment, the present invention includes a tap output collimator. The tap output collimator includes a means for projecting a portion of an incident optical beam into a tap output fiber for monitoring an optical signal transmitted to the tap output collimator. In a preferred embodiment, the means for projecting a portion of the optical output is a prism having a first and second inclined surfaces for projecting the portion of the incident light beam through the first inclined surface into the tap output fiber. The prism is further used for projecting the another portion of the incoming light beam through the second declined surface into the main output fiber. In a preferred embodiment, the prism is disposed in front of the tap output collimator with the first incline surface and the second incline surface. The position of the prism is arranged to have a surface area ratio relative to an incoming optical beam and the ratio is corresponding to a tapping out ration for projecting a predefined tapping out ratio of optical transmission to the tap out optical fiber.
In summary, this invention discloses an optical component that includes a built-in tap-out projection optical arrangement for projecting a portion of an incoming beam to a tap-out fiber and for projecting another portion to main transmission fiber. In one of the preferred embodiments, the built-in tap-out projection optical arrangement further includes a front surface having an incline angle for projecting a portion of an incoming beam to a tap-out fiber and another portion to main transmission fiber. In another preferred embodiment, the built-in tap-out projection optical arrangement further includes a prism having a pair of inclined front surfaces for projecting the incoming beam into an output beam and a tap out beam. In yet another preferred embodiment, the built-in tap-out projection optical arrangement further includes a partially reflective front surface and a reflective mirror projecting the incoming beam into an output beam and a tap out beam.
This invention further discloses a method of configuring an optical component for receiving an incoming optical signal by providing a means for projecting a tap-out portion of the incoming optical signal into a tap output detecting and measuring means. The tapping out portion is then used for detecting and measuring a power of the optical signal transmitted out from the optical component.
This invention further discloses a configuration of dual beam collimator that provides dual parallel, collimated beam from one collimator lens with adjustable distance between each other. The dual beam collimator benefits the optical component such as optical switches that require dual light beam separated by small distance.
These and other objects and advantages of the present invention will no doubt become obvious to those of ordinary skill in the art after having read the following detailed description of the preferred embodiment, which is illustrated in the various drawing figures.